FEL2011 - List of Authors (Vecchione, T.)

Paper

Title

Page

High QE, Low Emittance, Green Sensitive FEL Photocathodes Using K₂CsSb

179

H.A. Padmore, D. Dowell, J. Feng, T. Vecchione, W. Wan
LBNL, Berkeley, California, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
T. Rao, J. Smedley
BNL, Upton, Long Island, New York, USA

Funding: Work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy, under Contract No. DE-AC02-05CH11231, KC0407-ALSJNT-I0013, and DE-SC0005713.
We describe the development of photocathodes based on Potassium-Cesium-Antimonide that satisfy many of the key requirements of future light sources, such as robustness, high quantum efficiency when excited with visible light and low transverse emittance. We have demonstrated QE of 7% at 532 nm, a normalized transverse emittance of 0.36 μm at 543 nm and 3 MV/m field gradient[1]. We have also shown that the material can be relatively robust to residual water contamination and we have extracted current densities of 1 mA/mm² with very long lifetime. We believe that this work is an important step forward in FEL development where high repetition rate is required.
[1] Applied Physics Letters (submitted)

Slides TUOC3 [4.825 MB]

THPB14

APEX Project Phase 0 and I Status and Plans and Activities for Phase II

582

F. Sannibale, B.J. Bailey, K.M. Baptiste, J.M. Byrd, A.L. Catalano, D. Colomb, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J. Feng, D. Filippetto, G. Huang, S. Kwiatkowski, W.E. Norum, H.A. Padmore, C. F. Papadopoulos, G. Penn, G.J. Portmann, S. Prestemon, J. Qiang, D.G. Quintas, J.W. Staples, M.E. Stuart, T. Vecchione, M. Venturini, M. Vinco, W. Wan, R.P. Wells, M.S. Zolotorev, F.A. Zucca
LBNL, Berkeley, California, USA
M. J. Messerly, M.A. Prantil
LLNL, Livermore, California, USA
C. Pellegrini
UCLA, Los Angeles, California, USA
M. Yoon
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The APEX project at the Lawrence Berkeley National Laboratory is devoted to the development of a high repetition rate (MHz-class) electron injector for X-ray FEL applications. The injector is based on a new concept photo-gun, utilizing a normal conducting 187 MHz RF cavity operating in CW mode in conjunction with high quantum efficiency photocathodes able to deliver the required repetition rates with available laser technology. The APEX activities are staged in two phases. In Phase I, the electron photo-gun is constructed, tested and several different photo-cathodes, such as alkali antimonides, Cs₂Te [1], diamond amplifiers [2], and metals, are tested at full repetition rate. In Phase II, a pulsed linac is added for accelerating the beam at several tens of MeV to prove the high brightness performance of the gun when integrated in an injector scheme. Based on funding availability, after Phase II, the program could also include testing of new undulator technologies and FEL studies. The status of Phase I, in its initial experimental phase, is described together with plans and activities for Phase II and beyond.
[1] In collaboration with INFN-LASA, Milano, Italy.
[2] In collaboration with Brookhaven National Laboratory, Upton NY, USA

Paper	Title	Page
TUOC3	High QE, Low Emittance, Green Sensitive FEL Photocathodes Using K₂CsSb	179
	H.A. Padmore, D. Dowell, J. Feng, T. Vecchione, W. Wan LBNL, Berkeley, California, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA T. Rao, J. Smedley BNL, Upton, Long Island, New York, USA
	Funding: Work was supported by the Director, Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy, under Contract No. DE-AC02-05CH11231, KC0407-ALSJNT-I0013, and DE-SC0005713. We describe the development of photocathodes based on Potassium-Cesium-Antimonide that satisfy many of the key requirements of future light sources, such as robustness, high quantum efficiency when excited with visible light and low transverse emittance. We have demonstrated QE of 7% at 532 nm, a normalized transverse emittance of 0.36 μm at 543 nm and 3 MV/m field gradient[1]. We have also shown that the material can be relatively robust to residual water contamination and we have extracted current densities of 1 mA/mm² with very long lifetime. We believe that this work is an important step forward in FEL development where high repetition rate is required. [1] Applied Physics Letters (submitted)
	Slides TUOC3 [4.825 MB]

THPB14	APEX Project Phase 0 and I Status and Plans and Activities for Phase II	582
	F. Sannibale, B.J. Bailey, K.M. Baptiste, J.M. Byrd, A.L. Catalano, D. Colomb, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J. Feng, D. Filippetto, G. Huang, S. Kwiatkowski, W.E. Norum, H.A. Padmore, C. F. Papadopoulos, G. Penn, G.J. Portmann, S. Prestemon, J. Qiang, D.G. Quintas, J.W. Staples, M.E. Stuart, T. Vecchione, M. Venturini, M. Vinco, W. Wan, R.P. Wells, M.S. Zolotorev, F.A. Zucca LBNL, Berkeley, California, USA M. J. Messerly, M.A. Prantil LLNL, Livermore, California, USA C. Pellegrini UCLA, Los Angeles, California, USA M. Yoon POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The APEX project at the Lawrence Berkeley National Laboratory is devoted to the development of a high repetition rate (MHz-class) electron injector for X-ray FEL applications. The injector is based on a new concept photo-gun, utilizing a normal conducting 187 MHz RF cavity operating in CW mode in conjunction with high quantum efficiency photocathodes able to deliver the required repetition rates with available laser technology. The APEX activities are staged in two phases. In Phase I, the electron photo-gun is constructed, tested and several different photo-cathodes, such as alkali antimonides, Cs₂Te [1], diamond amplifiers [2], and metals, are tested at full repetition rate. In Phase II, a pulsed linac is added for accelerating the beam at several tens of MeV to prove the high brightness performance of the gun when integrated in an injector scheme. Based on funding availability, after Phase II, the program could also include testing of new undulator technologies and FEL studies. The status of Phase I, in its initial experimental phase, is described together with plans and activities for Phase II and beyond. [1] In collaboration with INFN-LASA, Milano, Italy. [2] In collaboration with Brookhaven National Laboratory, Upton NY, USA